Temperature-indicator.



P. l. STEENBJERG.

TEMPERATURE INDICATOR.

APPLICATION FILED JUNE 6. 1913.

1 ,272,554. Patented July 16, 1918.

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UNITED STATES PATENT QFFTCE.

PEDER J fiRGEN SEN STEENBJERG, 0F FREDERIKSBERG, NEAR COPENHAGEN,DENMARK.

TEMPERATURE-INDICATOR.

To all whom it may concern Be it known that I, Pnnnn JijncnxsnnSrnnzvnanno, of No. 6 l uglevangsvej, Frederiksberg, near Copenhagen, inthe Kingdom of Denmark, have invented certain new and usefulImprovements in or Relating to Temperature-lndicators; and I do herebydeclare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same, reference being had to theaccompanying drawings, and to letters or figures of reference markedthereon, which form a part of this specification.

As it is well known, various liquids when near their boiling point arevery sensitive to any further supply of heat, as near the boiling point,large fluctuations in the pressure of vapors correspond to fluctuationsof heat. The working of thermometers, heat regulators and otherapparatus which use such liquids as the operative medium, is howeververy unreliable, partly because unsaturated steam is formed and partlybecause saturated steam is again condensed.

According to this invention, in place of a liquid giving off vapors andcapable of being itself evaporated, a material is used as a pressureproducing medium for the above mentioned purposes, consisting of asubstance which in itself is the least capable of evaporating, but onbeing heated, gives off a gas in large quantities corresponding exactlyto the temperature at the moment, the said gas behaving above itscritical temperature like a saturated steam which cannot be condensed atthe temperatures and pressures in question, that is to say, remains inthese conditions a real gas. The pressure produced corresponds in suchcases exactly to the temperature at the time. By regulating thecounter-pressure, the reaction temperature of a device using suchmaterials can be adjusted as desired.

The materials in question represent therefore chemical combinationswhich are gradually decomposed by heating into a nonevaporating materialand gas which ingredients combine again on the temperature beingreduced. As an example of materials that can be used, may be mentionedcompounds of ammonia gas with metallic halogen salts, hybrids,bicarbonates, etc. It is not however essential that the non-gaseousingredient which forms an absorbing means Specification of LettersPatent.

Patented July 16, 1918. Serial No. 772,100.

for the gas should be a solid body. The said ingredient may be also aliquid (for instance a molten metal). At the temperature and pressuresin question, it must not be however capable of being evaporated, that isto say, it must not have any vapor pressure of its own. The substance ofthe invention will become clear by comparing for instance the compoundof silver chlorid with ammonia gas and an aqueous solution of ammoniagas. In the latter, in addition to the pressure of ammonia gas, that ofsuperheated easily condensing steam soon becomes noticeable, while inthe silver chlorid ammonia, the am monia gas released as the heatingincreases, represents the only pressure producer.

In the accompanying drawings Figure 1 is an elevation of one form of device embodying my invention, and

Fig. 2 is an elevation of a modified form.

In the devices shown, the fluctuations of temperature or thefluctuations of pressure of the regulating material inclosed in thereceiver 8, exactly corresponding to the said changes of temperature,move a liquid mass or a liquid thread 14, for instance of mercury, andin that Way in the construction shown in Fig. l the lever or beam 15 isturned, Or an electric contact 16 (maximum and minimum contact) isclosed, and then the said movement or the electric current transmittheir influence in any desired manner to the well known control orindicator devices (not shown).

When mercury is used for the changing the center of tacts or the like,and on the other hand chlorid of silver is used as a vehicle for theammonia gas, care must be taken to prevent mercury from passing intoreceptacle 8 containing the silver salt, so that the silver salt may notbe decomposed. To that end, in front of the tank 8 is arranged a bulb 17of such size that the whole quantity of mercury contained in the saidapparatus, does not fill the said bulb even to one-half. The pipe 11leading to the tank 8, opens with a fine point 18 into the ball 17, sothat mercury never enters the pipe 11. If owing to vibrations, in caseof an apparatus arranged horizontally or turned over, a drop of mercuryshould get into the pipe 11 18 it would be stopped in a second bulb 19arranged in front of the tank 8, in order to return to the ball 17 whenthe apparatus is again in the normal position. The

purpose of gravity, closmg conpipe 11 can be formed into a distantpressure transmitting pipe. v

The heating pipe 20 connected to the ball 1? (pressure connected to aclosed chambertfor instance a ball 21) of such capacity that in themovements in question of the liquid thread, the pressure of the gasinclo's'e'd in the said chamber is scarcely altered. The Whole apparatusis in that Way completely closed, and the absorbed or pressure producinggas is generated at a constant counter pressure (if desired at aVacuum); The pressure producing gas and the gas in'closed in the tank 21are preferably the same. Owing to the fact that when the apparatus isplaced horizontally or turned over, more or less passes from thepressure side of the apparatus (the tank 8) to the counter-pressure side(tank 21) the reaction temperature of the apparatus can be regulated asdesired.

The reaction temperature can be also modified by selecting for theWorking position of the apparatus a more or less oblique position. Tothat end, the apparatus shown chamber) is on the other hand v in Fig. 1,is arranged on the beam 15 in a rotatable manner by means of holders 22.The apparatus ceuiaalso be rotated about an axis at a right angle to the.plane of oscillations of the beam.

I claim: 1

In a temperature indicating device, a receptacle chlorid of silvertherein having chemically united therewith ammonia gas capable of beingliberated by heat and ch'emi cally reunited upon cooling, saidliberation and absorption being a function of the temper-'atureacontalner abody of mercury therein actuated by said gas, a chamber intowhich said mercury may be moved and containing a volume of like gascounteracting on said mercury, and means operated by the movement ofsaid mercury.

In testimony that I claim the foregoing as my invention, I have signedmy name in presence of two subscribing Witnesses.

PEDER JORGENSEN STEENBJERG. lVitnesse's:

ERNEST BOUTARD, Erin; Motm'rrzEN.

Copies 02 this p'atnt may be obtained for fife cents emit, by addressingare com issfc'ner 0f mam.

Washington, n. c.

